Drowning Ruth by Christina Schwartz

It all comes down to the shame associated with being unmarried and pregnant. Amanda comes home to hide her pregnancy, the night of the birth she tires to leave to escape a plan to give the baby to her sister. This results in a tragic accident when her toddler niece chases after her on the ice and her sister chases after her daughter. Sister, Mathilda, drowns. Amanda spins more lies all to hide the fact that the baby is hers. Things become more complicated as the children grow. The two girls meet at school and of course they become best friends. The baby's father moves to the neighborhood as a summer residence and his son eventually becomes friends with both girls. In order to prevent a potential marriage between half-siblings, Amanda finally tells all to her niece Ruth, that she raised as a daughter. Everything works out, although the family never escapes their oddness.